He is not just calling for self sufficiency... he is calling for a mobilization.
He is not just saying that there are not enough black entrepreneurs, he is saying that they need more black entrepreneurs for the blacks to buy from.
Just my opinion
And he's right. It is time they applied effort toward something constructive. Black entrepreneurs were equal to white entrepreneurs long before 1964. And they were a hell of a lot more equal then, than those who are still waiting for the government to enforce equality today.
Whether these folks are separatists is another issue. (and one I cannot discern from this article alone.) We need to support those who are espousing constructive behavior even when we may not buy into all their doctrines.